Berlin 2012 – scientific programme

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O: Fachverband Oberflächenphysik

O 17: Nanotribulogy

O 17.3: Talk

Monday, March 26, 2012, 16:30–16:45, A 053

Evolution of nanocrystalline iron surfaces with grain level roughness under sliding contact loads — •Pedro A. Romero, Tommi T. Järvi, and Michael Moseler — Fraunhofer-Institut für Werkstoffmechanik IWM, Wöhlerstraße 11, 79108 Freiburg, Deutschland

Iron systems like steel alloys are one of the main industrial materials in our technological society. Various iron based technologies could benefit from a more fundamental understanding of the nanoscale mechanisms dictating friction and wear in order to improve product performance, efficiency and lifetime. Here, we communicate results from large scale atomistic simulations of nanocrystalline iron systems encompassing hundreds of nanograins and millions of atoms. The constructed model captures the sliding induced plasticity and heating responsible for friction at the contacting interfaces. Controlled pressure simulations will bring forth distinct mechanisms dictating friction and wear in nanocrystalline iron surfaces such as the nucleation and arrest of dislocations at grain boundaries, grain growth, rotation and elongation, as well as grain boundary annealing and motion. The simulations will demonstrate that pure iron nanocrystalline systems prefer to coarsen interface grains while iron-carbon systems prefer to develop an amorphous boundary layer in order to mediate the sliding induced plastic deformation.